Abstract
The transport sector is one of the main contributors to air pollution in Brazilian urban centers. To address this, the Brazilian government implemented the Air Pollution Control Program for Motor Vehicles (PROCONVE) and the Air Pollution Control Program for Motorcycles and Similar Vehicles (PROMOT), aiming to regulate emissions from light-duty vehicles (LDVs), heavy-duty vehicles (HDVs), and motorcycles. This study evaluates the long-term effectiveness of these programs in the Metropolitan Region of Belo Horizonte (MRBH), a highly urbanized and industrialized area in southeastern Brazil. Results show that, between 1999 and 2020, while total fuel consumption and the vehicle fleet expanded by approximately 52% and 131%, respectively, average pollution levels declined by 46% over the same period. However, pollutant concentrations in the MRBH often exceed the World Health Organization (WHO) Air Quality Guidelines for long-term exposure, indicating ongoing public health risks. While the national programs have contributed to emission reductions through technological advances in vehicles and fuels, they have not been sufficient to ensure air quality levels that effectively protect public health. This study highlights the need for complementary measures focused on urban planning and transport management to reduce traffic volume and improve local air quality. Vehicle emission standards alone are insufficient to guarantee clean air in Brazilian urban centers. Broader progress requires integrated strategies combining cleaner technologies, fleet renewal, sustainable mobility policies, and climate-resilient transport systems.